Electrical signal switch



June 7, 1938. w, P, CROCKETT, JR 2,119,778

' ELECTRICAL SIGNAL SWITCH Filed April 25, 1936 &

I Illllllllll J abzzzeu Patented June 7, 1938 UNITED STATES PATENTOFFICE ELECTRICAL SIGNAL SWITCH Chicago, Ill.

Application April 25,

4 Claims.

The invention relates to an electrical signal switch, and particularlyto an electrical switch which is used in hospitals, sanitariums andother places where it is desired to signal and call a doctor, nurse orother attendant for service.

The primary object of the invention is to construct the parts of theswitch so that after the switch push button has been depressed by apatient, attendant or other person, causing a contact stem or plungerand a locking latch to be moved and locked, and the switch being thus inoperative and locked position with electrical current flowing andilluminating a visual signal, lamp or lamps, a definite manual turningor rotating op eration of the handle or cap of the switch is essentialto unlock and release the contact stem or plunger and the locking latchand break the contact or contacts, and cause the lamp or lamps to beextinguished.

It is an importantobject of the invention that after the switch has beenoperated to illuminate the lamp, or lamps, even though it accidentallyfalls on the floor or is knocked against the wall, bed or other object,the switch cannot be put out of its set, locked or operating positionsince it takes a positive turning operation of the handle of the switchby the doctor, nurse or other attendant to reset the switch, restore itto its normal inoperative position, and have it ready for the next call.

It is another object of the invention to obtain a quick and rapid returnof the switching mechanism to normal inoperative position by means ofspring, cam and swinging latch mechanism after the lamp or lamps havebeen illuminated and it is dseired to cause them to be extinguished.

A further object of the invention is to assemble the parts in such amanner that after the switch push button has been depressed and the lampor lamps have been illuminated, and while the lamp or lamps remainilluminated, the switch button may be still further depressed to operatean audible signal, bell or buzzer without the return of the push buttonto normal position.

The invention will be further understood by reference to the followingdescription and the accompanying drawing in which one embodiment of theinvention has been described and illustrated, but it will be understoodthat changes, variations and modifications may be made in the switch ofthe invention without departing from the spirit of the invention as setforth in the appended claims.

In the drawing:

Figure 1 is a full size side elevational view of 1936, Serial No. 76,366

the electrical signal switch of the invention showing the various partsin assembled relation with the contact stem out of electrical contact;

Figure 2 is a longitudinal sectional view of the electrical switch on anenlarged scale on the line 2-2 of Figure l and shows the contact stemout of electrical contact;

Figure 3 is a longitudinal sectional view of the electrical switch on anenlarged scale on the line 2-2 of Figure 1, but shows the contact stemin depressed condition and making contacts to cause the visual signal orlamps to operate, and also shows one of the spring contact members whichis used to cause an audible signal or buzzer to operate when the contactstem is further depressed;

Figure 4 is a detailed cross sectional view of the latch and the contactstem showing the latch having a special seat or segmental cam surfacefor a routed surface in the contact stem and shows the contact stem outof electrical contact;

Figure 5 is another detailed view of the latch and the contact stem withthe special segmental cam surface of the latch and the routed surface ofthe contact stem in physical contact with each other, from whichposition they cannot be sepa rated except by the positive turningoperation of the switch cap or handle;

Figure 6 is a plan view of the head or supporting member of theelectrical switch taken on the line 66 of Figure 2, showing the slot inwhich the spring operating arm moves;

Figure 7 is a plan view taken on the line l-'l of Figure 2 showing byfull lines the latch in its position while the lamp or lamps are notbeing il luminated and by dotted lines the latch in its position whilethe lamp, or lamps are being illuminated;

Figure 8 is a plan view somewhat similar to Figure 7 showing by fulllines the latch in its position while the lamp, or lamps are beingilluminated, and by dotted lines the latch in its position while thelamp or lamps are not being illminated;

Figure 9 is a side elevational View of a portion of the latch with itssegmental cam; and

Figure 10 is a cross sectional view of the latch on the line |0l0 ofFigure 9.

The electrical signal switch of the invention is a compact structurehaving contact springs which are connected to the terminals of a numberof wires which in turn are connected to visual signals, which may be atthe door of the patients room, at a switchboard, annunciator, hallway orother desired place, and also has a contact spring against the contactring or band 25.

for a terminal for an audible signal or buzzer. The electrical switchand its terminals are usually enclosed in a casing but for convenienceof illustration, the casing is not shown. The wires leading to thecontact springs also are not shown.

The terminal block I5 is provided with a plurality of slots l6, and inthese slots, the various contact springs are secured. Three posts ll, I8and i9 extend from the terminal block 55 and support the head 23, whichin turn is connected with the turning cap or handle 2i. Each of theposts ll, l8 and it] has a screw threaded portion at one end whichscrews into the head 23 and a central screw-threaded bore at theopposite end to receive the screw which passes through the terminalblock.

The contact stem or plunger, generally designated 22, is provided withtwo annular non-metallic or fiber rings and 2A with the inset annularmetallic contact member 25. This contact member or band 25 is seated ona ledge 26 of the fiber ring 23, and the fiber ring 24 is brought intoclose contact with it so that the contact band 2? is out of electricalcontact with the shaft 2i of the contact stem 22. The coil spring 28 isplaced upon the shaft 2? between the fiber ring 23 and the terminalblock iii. The inner end of the shaft 2? moves in the aperture shown at28 in the terminal block i5, and the other end of the shaft isscrew-threaded at 33 and a push button 3i of insulated material issecured thereon.

The shaft 27 is also provided with the collar 32 which has the enlargedcollar portion 33 which is against and holds the fiber ring 24 in placeAt the other end of the collar 32, there is an inwardly extendingannular cam surface 3 5.

The switch head 28 is provided with a swinging bar or latch 35 which ispivoted on the pivot post 36, one end of which is secured in the switchhead 2%]. The latch is provided with a post 31 to which one end of thecoil spring 38 is secured. The latch is also provided with the aperture39. At one side of the aperture 39, and extending to an outer edge ofthe latch 35 is the inclined cam surface 43. At the end of the latchopposite the pivot post 36, the latch is cut out at H and has theextended portion 42 which is adjacent the post ii at the end of themovement of the latch.

The spring 38 which has its one end secured to the post 3! has its otherend secured to the post 43, which latter post is on the under surface ofthe turning handle 2i. The post 43 which is integral with the handle 2iextends through the elongated slot as in the head 20. The pivot post 36has a head portion and a reduced screwthreaded portion, whichscrew-threaded portion extends through the aperture in the latch 35 andalso into an aperture in the head 28, where it is screw-threaded intoplace and serves as the pivot post for the latch 35. The post 37 has areduced portion around which the end of the spring 38 is secured. Asstated, the other end of the spring 38 is secured to the post 43.

The spring 38 has a two fold purpose and use. First, to pull the latch35 to cause the latch 35 to swing to place the segmental cam surface ii]in physical contact with the routed cam surface 34 of the contact stemand second, to return the cap or handle 2| to normal inoperativeposition after the handle has been turned to release the contact stem22. The switch head 26 has an annular shoulder or collar 45, the top ofwhich is adjacent the latch 35. The turning handle 2i is also providedwith an annular shoulder or collar 46 which is an integral part of theturning head 2i. This shoulder or collar 46 fits concentrically withinthe shoulder or collar 45 which is in the head 20. These collars turnwithin each other and are limited in their travel by the post 33 and theelongated slot 44. The inner periphcry of the collar 46 is rolled over awasher seated on the shoulder or collar 45 and holds the two collars inproper secured and turning relation.

In the operation of the electrical switch of the invention, as stated,the normal position of the parts before any signals are made is thatshown in Figure 2. It will be seen that the push button 3i is at itsextreme right-hand or outer position. The spring 33 is contracted andthe stud or pin 33 is in the elongated slot 44 in the position shown inFigure 6. The projecting end portion 42 of the latch 35 is restingagainst the supporting post ill. The cam surface 34 is not in contactwith the cam surface 65, but the enlarged portion 32 of the contact stem22 extends through the aperture 33 of the latch 35 (see Figs. 2 and 4).The fiber ring 24 with the adjoining contact band or ring 25 and thefiber ring 23 are toward the head 2i] and the handle 2i. At this time,the spring 28 is expanded and the end of the shaft 2'! is to the rightin the opening 29. Also at this time, the contact band or ring 25 is outof electrical contact with all of the contact springs which are fastenedin the terminal block [5.

It will be understood that there may be any number of these contactsprings secured in the block 65, and each of them is provided with anouter protecting or guard strip 4'! as shown. These guard strips are notin the electrical circuit but may be utilized by means of stampings toindicate the nature or character of the spring contact beneath. It willbe understood also that the contact ends of the contact springs 43 forthe visual or lamp signals are the long ones, and there may be a numberof these depending on. how many lamp signals are to be operated, andthat the contact end of the contact spring 49 for the audible or buzzersignal is the short one. It will also be understood that the two contactsprings 56 and SI are terminals of the battery circuit. The longerspring completes the circuit to the lamp or lamps by contacting with thering 25 when the contact stem 22 is partially depressed, and the shorterspring 50 completes the circuit to the bell or buzzer by contacting withthe ring 25 when the contact stem 22 is completely depressed.

While the parts which have been described are in the positions shown inFigure 2, the lamps are not burning nor is the buzzer operating. At thistime, the handle 2| may be moved a short distance against the action ofthe spring 38, and when thus moved, the post 43 is moved over againstone side of the latch 35, but this does not affect the operation of thesignal switch so far as the signaling is concerned.

When the push button 3| is depressed inwardly, as shown in Figure 3, thecontact stem 22 is also moved inwardly contracting the spring 28,causing the shaft 21 to move in the opening 29. The lamp springs 48 arethen brought into contact with the contact ring or band 25 causing thelamps to. be illuminated. At this time, the buzzer spring 49 is not incontact and therefore the buzzer is silent.

As the button 3| is being depressed to the lighting position, thecontact stem 22 is being moved inwardly. Simultaneously the latch 35 iscaused to swing on the pivot 36 to a position adjacent the post 43 andthe post 43 with the handle 2|, of which the post is an integral part,is held against the tension of the spring 38. When the button 3| isdepressed moving the contact stem 22 inwardly and against the action ofthe spring 28, the routed surface 34 travels on the segmental surface 40of the latch 35. The movement of the contact stem 22 being inwardly in astraight line with the surface 34 contacting the surface 40, causes thelatch 35 to swing away from the enlarged portion 32 of the contact stemand moves the part 42 away from the post H, as shown in the dotted lineposition, Figure '7.

As soon as the latch 35 snaps into this last mentioned position due tothe action of the spring 38, upon release of the thumb or finger fromthe push button 3|, the contact stem 22 moves outwardly a slightdistance and it seats and rests upon the recess surface 40 of the latch35. At this time, the two surfaces 40 and 34 are in physical contact atthe top portion of the inclined cam recess surface 40 and the contactstem 22 is in locked position on the latch 35 and cannot be releasedtherefrom except by the positive and manual turning or rotating actionin a clockwise direction of the handle or cap 2|. This inclined camsurface 40 being eccentrically arranged with respect to the aperture 39and the latch 35 being over to one side or in an offset position againstthe post 43, it will be understood that the enlarged portion 32 of thecontact stem is eccentrically poised with respect to and before theaperture 39. At this time, the push button is inwardly depressed, butnot to its full extent. In this locked position, the lighting or visualsignals are burning or operating ready for the response of the nurse orother attendant, since the contact 25 completes the lighting circuits,through the battery spring 5| as has been ex plained.

Upon further depression of the contact stem 22, the lamps becomeextinguished because the contact band 25 has been forced inwardly awayfrom the spring terminals 48 and the contact 25 has been brought intocontact with the bell or buzzer spring terminal 49 and the batteryspring 50. In order to cause the buzzer to sound, it is necessary tokeep the push button 3| depressed by action of the thumb or finger andagainst the action of the spring 28. When so depressed to its limit, thelamps extinguish, but the buzzer sounds.

If the patient or other person should become impatient because of lackof attendance by the nurse or other attendant, the push button may beintermittently depressed from its first position, with the lampsburning, to its second position, with the lamps out but the buzzersounding, thus causing a flickering of the lights at the door,annunciator, switchboard or other place, and also the intermittentsounding of the buz- Zer. Until the handle 2| is turned, either thelamps are burning or the buzzer is sounding since the push button 3|remains depressed, that is, in either its first depressed position or inits second depressed position.

When the contact stem 22 is moved away from the lighting position to theringing or sounding position, the surfaces 34 and 40 are disconnectedfrom each other since the contact stem 22 is moved away from the latch35, but the latch remains stationary and does not move. Upon release ofthe thumb or finger from the button 3|, the stem 22 with the button 3|moves outwardly and the inclined routed surface 34 resumes contact withthe inclined cam recess surface 4|]. In so doing, however, it does notdisturb the latch 35 since that remains stationary on its pivot 36 andagainst the under surface of the head 20. All of this time, the latch 35keeps the way barred for the return of the stem 22 and locks it andprevents its return to the full outward position until and unless thehandle or cap 2| is turned or revolved to move the latch 35 and get therecess surface 40 out of the way.

When the nurse or other attendant responds to the call initiated by theoperation of the electrical switch, the release and unlocking of theswitch is effected by merely turning the handle 2| a short distance in aclockwise direction. As stated, a very important point in connectionwith the electrical switch of the invention is the fact that the switchmay be turned off by the turning or revolving of the handle or cap asdistinguished from the depression of an auxiliary button, lever or othercontrivance such as is generally used.

It may also be released by one hand instead of two hands. In otherwords, the entire device may be held in the hand and the handle 2|turned by the thumb and a finger of that hand. This is an importantfeature, because the nurse or other attendant may have a tray,instruments or other articles or devices in one hand, thus leaving theother hand free to operate the switch and turn out the lamps.

As has been stated, the release and unlocking of the contact stem 22with the contact band 25 is effected by the turning of the handle or cap2| in a clockwise direction. As the cap is turned, the post 43 travelsalongside the side of the latch 35, against the action of the spring 38,and swings the latch on the pivot 36 and causes the portion 42 of thelatch to move toward the post i1. As the latch 35 is being forced by thepost 43, the latch 35 slides and causes the inclined cam recess surface40 to become disengaged from the routed surface 34. When the post 43 hasreached its limit of movement in the slot 44 and the two surfaces 34 and40 have become disengaged, the enlarged portion 32 is before theaperture 39 and the contact stem 22 snaps into the aperture 39 due tothe release and unlocking operation which has been described, includingthe action of the spring 28. This reverses the button 3| from theposition shown in Figure 3 back to the position shown in Figure 2, andready to be used again for signaling by the patient.

What I claim and desire to secure by Letters Patent is:

1. In an electrical signal switch the combination of a handle, a signalspring, a spring connected with a source of power, a contact stemadapted to electrically connect said springs, a swinging flat latch,said latch and said stem having cooperative means for making andbreaking said electrical connection, said means consisting of asegmental inclined cam cut in one surface of said latch and an inclinedsurface in said stem with which said segmental inclined cam connects,said flat latch being pivoted to cause said segmental inclined camsurface to travel on the inclined surface of said stem because of theturning of said handle, a coil spring, the action of the handle beingpartly controlled by the spring, one end of the spring being attached tosaid fiat latch adjacent its pivoted end and the other end to a studintegrally secured to said handle.

2. In an electrical signaling switch the combination of a handle, ahead, said handle having a collar and adapted to turn in said head, aterminal block, said terminal block and head being connected together, acontact stem extending through said handle and head and into saidterminal block, said contact stem being spring-operated and having acontact band, battery, lamps and buzzer springs secured in said terminalblock, the ends thereof adapted to con tact with said contact band, aswinging flat latch, said latch having an inclined segmental cam surfacecut in one surface of said latch and said contact stem having aninclined cam surface, said cam surfaces registering and contacting witheach other on operation of said contact stem, said contact stem beingoperable to at one time illuminate said lamps and at another time tosound said buzzer, said contact stem being released by the turning ofsaid handle and the swinging of said latch, said latch being pivoted atone end to said head and having a coil spring connected adjacent thepivoted end of said latch, a stud on said handle, an elongated aperturein said head, said stud extending through said elongated aperture, theother end of the latch coil spring being secured to said stud to operatesaid latch and place it in position to permit the con tact stem toregister and contact with said latch cam surface whereby said contactstem and battery and lamp contacts are made.

3. In an electrical signaling switch the combination of a handle, ahead, Said handle having a collar and adapted to turn in said head, aterminal block, said terminal block and head being connected together, acontact stem extending through said handle and head and into saidterminal block, said contact stem being spring-operated and having acontact band, battery, lamps and buzzer springs secured in said terminalblock, the ends thereof adapted to contact with said contact band, aswinging flat latch, said latch having a cam surface cut in one surfaceof said latch and said contact stem having an inclined cam surface, saidcam surfaces registering and contacting with each other on operation ofsaid contact stem, said contact stem being operable latch coil springbeing secured to said stud to operate said latch and place it inposition to permit the contact stem to register and contact with saidlatch cam surface whereby said contact stem and battery and lampcontacts are made and also holding said latch in position by the actionof the latch coil spring while the contact stem is further depressed tosound the buzzer on further depression of said contact stem and notpermitting the release of the contact stem, battery and lamp contactsuntil the turning of said handle and the swinging of said latch.

4. In an electrical signaling switch the combination of a handle whichturns, a latch operating stud secured to said handle, a collar on saidhandle, a head, said head having a central aperture and a collarsurrounding said aperture, and also an elongated aperture along one sideof its collar for the reception of the stud secured to said handle, thehandle collar fitting and turning within the head collar and the studsimultaneously turning in the elongated aperture in the head, a swingingfiat latch pivoted in said head, said latch having an aperture, a coilspring secured to the adjacent pivot end of said flat latch and also tothe handle stud to operate said latch, a segmental inclined cam cut inone surface of said latch adjacent said aperture, a contact stem, saidstem having an electrical contact, said stem also having an enlargedportion and a routed cam surface within said enlarged portion adapted tocontact and register with the cam surface of said latch, a coil springadapted to force said stem into position against the cam surface of saidlatch, said cam surfaces of said latch and said stem being releasable bythe turning of said handle,

WILLIAM P. CROCKETT, JR.

